One of the men accused of murdering Stephen Lawrence may have picked up traces of forensic evidence when visiting one of the attackers, a court heard today.
Forensic scientist Roy Green told a jury at the Old Bailey that one of the scenarios he considered during his research was that David Norris had visited one of the killers and picked up fibres on his clothes.
A team of experts found six green fibres matching Mr Lawrence's trousers and one matching his T-shirt linked to a sweatshirt seized from Norris' house.
Today Stephen Batten QC, for Norris, asked Mr Green: "What you postulated to yourself is that he might know one of the real assailants for example, and have gone round to their address?"
Mr Green said: "That was one of the scenarios that I considered, yes."
Yesterday the fibres expert told the court that he had also looked at the possibility that the sweater was washed after the attack.
But Mr Batten told him "you haven't a clue whether it was washed or not", and said he had only mentioned it because there were only a few fibres found.
Mr Green said: "It was offered as one of the many scenarios which I had considered."
The fibres were found distributed all over the sweatshirt, which Mr Green said might be due to the garment being moved around after it was seized.
He added: "We do have to remember that what we see here is what remains after other fibres have fallen off and so it doesn't necessarily give a completely true picture of what was originally there."
Norris, 35, and Gary Dobson, 36, deny taking part in the gang attack in which Mr Lawrence was killed in Eltham, south-east London, in 1993.
Mark Gatley, also for Norris, said that hairs with 13 different maternal DNA profiles were found on clothes seized from Norris' house.
Forensic scientist Deborah Hopwood agreed that the hairs could have got on to the clothing by both direct contact and indirect means.
Mr Gatley said: "The possibility exists then that these hairs may have accumulated on his clothes through secondary transfer as well as direct transfer."
She replied: "Yes there's a possibility of secondary transfer."
One hair, 2mm in length, that matched Mr Lawrence's maternal DNA - meaning that it came from him or a relative in the maternal line of his family - was found on jeans seized from Norris' house.
The court was told that there was no way of knowing if the hair got on to the jeans by direct contact between Norris and Mr Lawrence, or indirectly.
Mr Gatley said: "You couldn't exclude the possibility that it had originally been deposited from a different item of clothing and then had been transferred secondarily on to the jeans during the time prior to the recovery of the jeans by the police."
Mrs Hopwood replied: "Yes that's right."
The jury was told that Dobson, Norris and two other men not on trial, Neil and Jamie Acourt, had hairs from the same dog on their clothing.
In total on all the clothes seized from their homes there were hairs from 15 separate dogs, two cats and one pig.
On Mr Lawrence's clothing there were hairs from four cats, two dogs and one from a cow.
The jury was told that this suggested that the animal hairs could have been picked up on the clothing by indirect means.
The trial was adjourned until tomorrow.